1. APPELMANS, M., MICHIELS, J., NELIS, J., and MASSA, J. M. (1961). Bull. Soc. belge Ophtal., 128, 249.
2. ATKINS, L. and ROSENTHAL, M. K. (1961). New Engl. J. Med., 265, 314. DowN, J. L. (1866). Lond. Hosp. Rep., 3, 259.
3. EDWARDS, J. H., HARNDEN, D. G., CAMERON, A. H., CROSSE, V. M., and WOLFF, 0. H. (1960). Lancet, 1, 787.
4. Diseases of the Nervous System in Infancy, Childhood and Adolescence.;FoRD, F.R.,1960
5. HAYWARD, M. D., and BOWER, B. D. (1960). Lancet, 2, 844.